Lubricant composition

ABSTRACT

A lubricant composition has an increased oxidation induction time. The lubricant composition includes a base oil present in an amount of greater than 85 parts by weight per 100 parts by weight of the lubricant composition. The lubricant composition also includes an antioxidant component including particular first, second, and third antioxidants.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to a lubricant composition that has an increased oxidation induction time and that includes a base oil and an antioxidant component. More specifically, the antioxidant component includes three particular antioxidants.

BACKGROUND

Lubricant compositions are generally well known in the art and are typically categorized as engine oils, driveline system oils, gear oils, greases, automatic and manual transmission fluids and oils, hydraulic oils, industrial gear oils, turbine oils, rust and oxidation (R&O) inhibited oils, compressor oils, or paper machine oils, etc. Each of these compositions has particular specifications and design requirements and most are designed to minimize corrosion and wear, to resist thermal and physical breakdown, and to be able to minimize the effects of common contaminants such as oxidizing compounds and metal fragments.

Additives such as antioxidants can be utilized to improve corrosion and wear resistance of the compositions. However, during use, acids tend to form and accumulate in the compositions. These acids typically break down common antioxidants which leads to the compositions having decreased useable lifetimes. For example, as the amount of acid builds up in the compositions, antioxidants are typically degraded and the oxidation induction times of the compositions typically decrease. Accordingly, there remains an opportunity to develop an improved lubricant composition.

SUMMARY OF THE DISCLOSURE

This disclosure provides a lubricant composition having an increased oxidation induction time determined according to ASTM D6186. The lubricant composition includes a base oil present in an amount of greater than 85 parts by weight per 100 parts by weight of the lubricant composition. The lubricant composition also includes an antioxidant component. The antioxidant component includes a first antioxidant, a second antioxidant, and a third antioxidant. The first antioxidant has the structure:

wherein R is a straight or branched alkyl group of from 7 to 17 carbon atoms, and wherein n is from 6 to 18. The second antioxidant has the structure:

wherein each of A, D, E and G is carbon or nitrogen and wherein R² and R³ are each independently chosen from hydrogen, alkyl, N-(alkyl)₂, styryl, and α-alkyl styryl groups, provided that at least one of R² and R³ is not hydrogen. The third antioxidant has the structure:

wherein m is a number from 1 to 10 and R⁴ is hydrogen or an alkyl group having 1 to 12 carbon atoms, and wherein R⁵ is an alkyl group having 1 to 20 carbon atoms and each of R⁶ and R⁷ is independently —CH₂—S-alkyl, wherein the alkyl group bonded to the sulfur atom has 1 to 20 carbon atoms.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure provides a lubricant composition. In various embodiments, the lubricant composition can be further described as a fully formulated lubricant or alternatively as an engine oil. In one embodiment, the terminology “fully formulated lubricant” refers to a total final composition that is a final commercial oil. This final commercial oil may include, for instance, detergents, dispersants, antioxidants, antifoam additives, pour point depressants, viscosity index improvers, anti-wear additives, friction modifiers, and other customary additives. In the art, engine oils may be referred to as including a base oil as described below and performance additives.

The lubricant composition (hereinafter referred to as “composition”) includes a base oil and an antioxidant component, each of which is described in greater detail below. The lubricant composition may also include any one or more additives known to those in the art. In various embodiments, the base oil is, consists essentially of, or consists of the base oil, the antioxidant component, and optionally one or more additives described herein. The composition may be free of one or more additives described herein or free of any one or more additives known in the art. The language “consists essentially of” describes various embodiments wherein the composition is free of one or more polymers, monomers, antioxidants, and/or additives described herein or known in the art.

Base Oil:

The base oil is not particularly limited and may be further defined as including one or more oils of lubricating viscosity such as natural and synthetic lubricating or base oils and mixtures thereof. In one embodiment, the base oil is further defined as a lubricant. In another embodiment, the base oil is further defined as an oil of lubricating viscosity. In still another embodiment, the base oil is further defined as a crankcase lubricating oil for spark-ignited and compression ignited internal combustion engines, including automobile and truck engines, two-cycle engines, aviation piston engines, and marine and railroad diesel engines. Alternatively, the base oil can be further defined as an oil to be used in gas engines, stationary power engines, and turbines. The base oil may be further defined as a heavy or light duty engine oil. In one embodiment, the base oil is further defined as a heavy duty diesel engine oil. Alternatively, the base oil may be described as an oil of lubricating viscosity or lubricating oil, for instance as disclosed in U.S. Pat. No. 6,787,663 and U.S. 2007/0197407, each of which is expressly incorporated herein by reference in one or more non-limiting embodiments. Alternatively, the base oil may be used in or as an engine oil, driveline system oil, gear oil, grease, automatic and manual transmission fluid or oil, hydraulic oil, industrial gear oil, turbine oil, rust and oxidation (R&O) inhibited oil, compressor oil, or paper machine oil, etc.

The base oil may be further defined as a base stock oil. Alternatively, the base oil may be further defined as a component that is produced by a single manufacturer to the same specifications (independent of feed source or manufacturer's location) that meets the same manufacturer's specification and that is identified by a unique formula, product identification number, or both. The base oil may be manufactured or derived using a variety of different processes including but not limited to distillation, solvent refining, hydrogen processing, oligomerization, esterification, and re-refining. Re-refined stock is typically substantially free from materials introduced through manufacturing, contamination, or previous use. In one embodiment, the base oil is further defined as a base stock slate, as is known in the art.

Alternatively, the base oil may be derived from hydrocracking, hydrogenation, hydrofinishing, refined and re-refined oils or mixtures thereof or may include one or more such oils. In one embodiment, the base oil is further defined as an oil of lubricating viscosity such as a natural or synthetic oil and/or combinations thereof. Natural oils include, but are not limited to, animal oils and vegetable oils (e.g., castor oil, lard oil) as well as liquid petroleum oils and solvent-treated or acid-treated mineral lubricating oils such as paraffinic, naphthenic or mixed paraffinic-naphthenic oils.

In various other embodiments, the base oil may be further defined as an oil derived from coal or shale. Non-limiting examples of suitable oils include hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene-isobutylene copolymers, poly(1-hexenes), poly(1-octenes), poly(1-decenes), and mixtures thereof; alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, and di(2-ethylhexyl)-benzenes); polyphenyls (e.g., biphenyls, terphenyls, and alkylated polyphenyls), alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs, and homologs thereof.

In still other embodiments, the base oil may be further defined as a synthetic oil which may include one or more alkylene oxide polymers and interpolymers and derivatives thereof wherein terminal hydroxyl groups are modified by esterification, etherification, or similar reactions. Typically, these synthetic oils are prepared through polymerization of ethylene oxide or propylene oxide to form polyoxyalkylene polymers which can be further reacted to form the oils. For example, alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methylpolyisopropylene glycol ether having an average molecular weight of 1,000; diphenyl ether of polyethylene glycol having a molecular weight of 500-1,000; and diethyl ether of polypropylene glycol having a molecular weight of 1,000-1,500) and/or mono- and polycarboxylic esters thereof (e.g. acetic acid esters, mixed C₃-C₈ fatty acid esters, or the C₁₃ oxo acid diester of tetraethylene glycol) may also be utilized.

In even further embodiments, the base oil may include esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids and alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acids, and alkenyl malonic acids) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, and propylene glycol). Specific examples of these esters include, but are not limited to, dibutyl adipate, di(2-ethylhexyl sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid, and combinations thereof. Esters useful as the base oil or as included in the base oil also include those formed from C₅ to C₁₂ monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tripentaerythritol.

The base oil may be alternatively described as a refined and/or re-refined oil, or combinations thereof. Unrefined oils are typically obtained from a natural or synthetic source without further purification treatment. For example, a shale oil obtained directly from retorting operations, a petroleum oil obtained directly from distillation, or an ester oil obtained directly from an esterification process and used without further treatment, could all be utilized in this disclosure. Refined oils are similar to the unrefined oils except that they typically have undergone purification to improve one or more properties. Many such purification techniques are known to those of skill in the art such as solvent extraction, acid or base extraction, filtration, percolation, and similar purification techniques. Re-refined oils are also known as reclaimed or reprocessed oils and often are additionally processed by techniques directed to removal of spent additives and oil breakdown products.

The base oil may alternatively be described as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. In other words, the base oil may be further described as one or a combination of more than one of five base oil groups: Group I (sulfur content >0.03 wt %, and/or <90 wt % saturates, viscosity index 80-120); Group II (sulfur content less than or equal to 0.03 wt %, and greater than or equal to 90 wt % saturates, viscosity index 80-120); Group III (sulfur content less than or equal to 0.03 wt %, and greater than or equal to 90 wt % saturates, viscosity index greater than or equal to 120); Group IV (all polyalphaolefins (PAO's)); and Group V (all others not included in Groups I, II, III, or IV). In one embodiment, the base oil is selected from the group consisting of API Group I, II, III, IV, V and combinations thereof. In another embodiment, the base oil is selected from the group consisting of API Group II, III, IV, and combinations thereof. In still another embodiment, the base oil is further defined as an API Group II, III, or IV oil and includes a maximum of about 49.9 wt %, typically up to a maximum of about 40 wt %, more typically up to a maximum of about 30 wt %, even more typically up to a maximum of about 20 wt %, even more typically up to a maximum of about 10 wt % and even more typically up to a maximum of about 5 wt % of the lubricating oil an API Group I or V oil. It is also contemplated that Group II and Group II basestocks prepared by hydrotreatment, hydrofinishing, hydroisomerzation or other hydrogenative upgrading processes may be included in the API Group II described above. Moreover, the base oil may include Fisher Tropsch or gas to liquid GTL oils. These are disclosed for example in U.S. 2008/0076687, which is expressly incorporated herein by reference in one or more non-limiting embodiments.

The base oil is typically present in the composition in an amount of greater than 85, e.g. from 85 to 99.9, from 90 to 99.9, from 85 to 95, or from 85 to 90, parts by weight per 100 parts by weight of the composition. Alternatively, the base oil may be present in amounts of greater than 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99, parts by weight per 100 parts by weight of the composition. In various embodiments, the amount of lubricating oil in a fully formulated lubricant (including diluent or carrier oils presents) is from about 85 to about 99.5 percent by weight, for example, from about 85 to about 96 percent by weight, for instance from about 90 to about 95 percent by weight. Of course, the weight percent of the base oil may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Antioxidant Component:

The antioxidant component includes or is a combination of three antioxidants, i.e., a first antioxidant, a second antioxidant, and a third antioxidant. Combinations of one or more first antioxidants may be used with one or more second antioxidants and one or more third antioxidants. In other words, one or more than one first antioxidant may be used. One or more than one second antioxidant may be used and one or more than one third antioxidant may be used. The antioxidant component (and the composition as a whole) may be free of or include less than 10, 5, 1, 0.5, 0.1, or 0.05, weight percent of one or more additional antioxidants that are not representative of the first, second, and third antioxidants.

The first antioxidant has the structure:

wherein R is a straight or branched alkyl group having 7 to 17 carbon atoms. In various embodiments, the alkyl group has 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 carbon atoms. In other embodiments, the alkyl group has 8 to 17, 9 to 15, 10 to 14, 11 to 13, 8 to 14, 10 to 12, or 11, carbon atoms. Moreover, n is from 6 to 18. In various embodiments, n is 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18. In other embodiments, n is from 7 to 17, 8 to 16, 9 to 15, 10 to 14, 11 to 13, or 11 or 12. In additional non-limiting embodiments, all values and ranges of values including those above, and therebetween, are hereby expressly contemplated. Moreover, all isomers of the aforementioned compounds are hereby expressly contemplated in various non-limiting embodiments. The language “and/or” describes that the first antioxidant may include molecules of the first structure above (e.g. to the exclusion of molecules of the second structure), molecules of the second structure above (e.g. to the exclusion of molecules of the first structure), or a combination of molecules of both the first and second structures above.

The second antioxidant has the structure:

wherein each of A, D, E and G is carbon or nitrogen and wherein R² and R³ are each independently chosen from hydrogen, alkyl, N-(alkyl)₂, styryl, and α-alkyl styryl groups, provided that at least one of R² and R³ is not hydrogen. Each of R² and R³ may be present at any location on their respective rings.

In various embodiments, one or more of the alkyl groups described immediately above has 1 to 20 carbon atoms. In various embodiments, one or more of the alkyl groups has 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 carbon atoms. In other embodiments, one or more of the alkyl groups has 2 to 19, 3 to 18, 4 to 17, 5 to 16, 6 to 15, 7 to 14, 8 to 13, 9 to 12, 10, or 11, carbon atoms. For example, one or more of the alkyl groups may be a methyl group, ethyl group, butyl group, etc. up to and including groups having 20 carbon atoms, and all isomers thereof. Similarly, the α-alkyl portion of the α-alkyl styryl group may have a number of carbon atoms as is described above. One or more of the alkyl groups may be linear, branched, cyclic, etc. In various embodiments A, D, E, and/or G may be carbon or nitrogen. For example, the compound may be further described as a pyridine or pyrimidine, e.g. and include one or two nitrogen atoms in the ring at any position. In additional non-limiting embodiments, all values and ranges of values including those above, and therebetween, are hereby expressly contemplated. Moreover, all isomers of the aforementioned compounds are hereby expressly contemplated in various non-limiting embodiments.

In other embodiments, the second antioxidant is one or more of the following:

wherein the alkyl groups are as described above.

The third antioxidant has the structure:

wherein m is a number from 1 to 10 and R⁴ is hydrogen or an alkyl group having 1 to 12 carbon atoms, and wherein R⁵ is an alkyl group having 1 to 20 carbon atoms and each of R⁶ and R⁷ is independently —CH₂—S—alkyl, wherein the alkyl group bonded to the sulfur atom has 1 to 20 carbon atoms. The —OH group, and each of R⁵, R⁶, and R⁷ may be located at any location on the ring. In various embodiments, m is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In other embodiments, the alkyl group has 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, carbon atoms. In various embodiments, the alkyl group has 2 to 11, 3 to 10, 4 to 9, 5 to 8, 6 or 7, carbon atoms. Any one or more alkyl groups may include heteroatom substitution (e.g. S, O, N) & bis substitution. In additional non-limiting embodiments, all values and ranges of values including those above, and therebetween, are hereby expressly contemplated. Moreover, all isomers of the aforementioned compounds are hereby expressly contemplated in various non-limiting embodiments.

In one embodiment, the third antioxidant has the following structure or is an isomer thereof:

In another embodiment, the third antioxidant has the following structure or is an isomer thereof:

wherein the alkyl group is as described above.

In still another embodiment, the third antioxidant has the following structure or is any isomer thereof:

The individual amounts of the first, second, and third antioxidants are not particularly limited. Similarly, the overall total amount of the first, second, and third antioxidants is not particularly limited. In various embodiments, the first, second, and third antioxidants are present in a ratio of from 0.1:0.1:0.1 to 3:5:5. Each one or more of these values of the ratio may itself be, for example, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5, or any range or value of ranges therebetween, all of which are expressly contemplated in various non-limiting embodiments. In various embodiments the first, second, and/or third antioxidants may each be present in the ratio of 0.1 to 2 or 0.1 to 3. In other embodiments, the overall total amount of the first, second, and third antioxidants, is from 0.1 to 2, 0.1 to 3, from 0.1 to 5, or from 0.1 to 5, parts by weight per 100 parts by weight of the composition. All values or range of values, both whole and fractional, within those ranges and values described above are hereby expressly contemplated in various non-limiting embodiments.

Additives:

The composition can additionally include one or more additives to improve various chemical and/or physical properties. Non-limiting examples of the one or more additives include anti-wear additives, metal passivators, rust inhibitors, viscosity index improvers, pour point depressors, dispersants, detergents, and antifriction additives. In addition, one or more addition antioxidants, apart from the ones described above, may be utilized or may be excluded. In various embodiments, additives are included such that the composition is commonly referred to as an engine oil or as an industrial oil, such as a hydraulic fluid, a turbine oil, an R&O (rust and oxidation inhibited) oil or a compressor oil.

Anti-Wear Additive:

The anti-wear additive is not particularly limited and may be any known in the art. It may be ash-containing or ash-less. In one embodiment, the anti-wear additive is chosen from ZDDP, zinc dialkyl-dithio phosphates, and combinations thereof. Alternatively, the anti-wear additive may include sulfur- and/or phosphorus- and/or halogen-containing compounds, e.g. sulfurised olefins and vegetable oils, zinc dialkyldithiophosphates, alkylated triphenyl phosphates, tritolyl phosphate, tricresyl phosphate, chlorinated paraffins, alkyl and aryl di- and trisulfides, amine salts of mono- and dialkyl phosphates, amine salts of methylphosphonic acid, diethanolaminomethyltolyltriazole, bis(2-ethylhexyl)aminomethyltolyltriazole, derivatives of 2,5-dimercapto-1,3,4-thiadiazole, ethyl 3-[(diisopropoxyphosphinothioyl)thio]propionate, triphenyl thiophosphate (triphenylphosphorothioate), tris(alkylphenyl) phosphorothioate and mixtures thereof (for example tris(isononylphenyl) phosphorothioate), diphenyl monononylphenyl phosphorothioate, isobutylphenyl diphenyl phosphorothioate, the dodecylamine salt of 3-hydroxy-1,3-thiaphosphetane 3-oxide, trithiophosphoric acid 5,5,5-tris[isooctyl 2-acetate], derivatives of 2-mercaptobenzothiazole such as 1-[N,N-bis (2-ethylhexyl)aminomethyl]-2-mercapto-1H-1,3-benzothiazole, ethoxycarbonyl-5-octyldithio carbamate, and/or combinations thereof. In one embodiment, the anti-wear additive include phosphorous and sulfur, e.g. in phosphorothionates and/or dithiophosphate esters.

The anti-wear additive is typically present in the composition in an amount of from 0.1 to 20, from 0.5 to 15, from 1 to 10, from 5 to 10, from 5 to 15, from 5 to 20, from 0.1 to 1, from 0.1 to 0.5, or from 0.1 to 1.5, parts by weight per 100 parts by weight of the composition. Alternatively, the anti-wear additive may be present in amounts of less than 20, less than 15, less than 10, less than 5, less than 1, less than 0.5, or less than 0.1, parts by weight per 100 parts by weight of the composition. It is also contemplated that the antiwear additive may be present in an amount of from 0.2 to 0.8, from 0.2 to 0.6, from 0.2 to 0.4, or from 0.3 to 0.5, parts by weight per 100 parts by weight of the composition. Of course, the weight percent of the anti-wear additive may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Additional Antioxidants:

The composition may include or be free of additional antioxidants other than the aforementioned first, second, and third antioxidants. In other words, the composition may include the first, second, and third antioxidants and not include one or more of any of the additional antioxidants described below. However, it is contemplated that, in various non-limiting embodiments, one or more of the additional antioxidants described below may be used in conjunction with the first, second, and third antioxidants described above.

Suitable, non-limiting, additional antioxidants include alkylated monophenols, for example 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(α-methylcyclohexyl)-4,6-dimethylphenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-methoxymethylphenol, 2,6-di-nonyl-4-methylphenol, 2,4-dimethyl-6(1′-methylundec-1′-yl)phenol, 2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol, 2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol, and combinations thereof.

Other non-limiting examples of suitable additional antioxidants includes alkylthiomethylphenols, for example 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,4-dioctylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-didodecylthiomethyl-4-nonylphenol, and combinations thereof. Hydroquinones and alkylated hydroquinones, for example 2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl stearate, bis-(3,5-di-tert-butyl-4-hydroxyphenyl) adipate, and combinations thereof, may also be utilized.

Furthermore, hydroxylated thiodiphenyl ethers, for example 2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol), 4,4′-thiobis(6-tert-butyl-3-methylphenol), 4,4′-thiobis(6-tert-butyl-2-methylphenol), 4,4′-thiobis-(3,6-di-sec-amylphenol), 4,4′-bis-(2,6-dimethyl-4-hydroxyphenyl) disulfide, and combinations thereof, may also be used.

It is also contemplated that alkylidenebisphenols, for example 2,2′-methylenebis(6-tert-butyl-4-methyl phenol), 2,2′-methylenebis(6-tert-butyl-4-ethylphenol), 2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol], 2,2′-methylenebis(4-methyl-6-cyclohexylphenol), 2,2′-methylenebis (6-nonyl-4-methylphenol), 2,2′-methylenebis(4,6-di-tert-butylphenol), 2,2′-ethylidenebis (4,6-di-tert-butylphenol), 2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2′-methylenebis [6-(α-methylbenzyl)-4-nonylphenol], 2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol], 4,4′-methylenebis(2,6-di-tert-butylphenol), 4,4′-methylenebis(6-tert-butyl-2-methylphenol), 1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methyl phenol, 1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl) butane, 1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercapto butane, ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate], bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene, bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate, 1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane, 2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane, 1,1,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methyl phenyl)pentane, and combinations thereof may be utilized as additional antioxidants.

O-, N- and S-benzyl compounds, for example 3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether, octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tris-(3,5-di-tert-butyl-4-hydroxybenzyl)amine, bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithiol terephthalate, bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, isooctyl-3,5di-tert-butyl-4-hydroxy benzylmercaptoacetate, and combinations thereof, may also be utilized.

Hydroxybenzylated malonates, for example dioctadecyl-2,2-bis-(3,5-di-tert-butyl-2-hydroxybenzyl)-malonate, di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)-malonate, di-dodecylmercaptoethyl-2,2-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate, bis [4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate, and combinations thereof are also suitable for use as additional antioxidants.

Triazine Compounds, for example 2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenyl propionyl)-hexahydro-1,3,5-triazine, 1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate, and combinations thereof, may also be used.

Additional suitable, but non-limiting examples of additional antioxidants include aromatic hydroxybenzyl compounds, for example 1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol, and combinations thereof. Benzylphosphonates, for example dimethyl-2,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl-5-tert-butyl-4-hydroxy 3-methylbenzylphosphonate, the calcium salt of the monoethyl ester of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid, and combinations thereof, may also be utilized. In addition, acylaminophenols, for example 4-hydroxylauranilide, 4-hydroxystearanilide, octyl N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.

Esters of [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, and combinations thereof, may also be used. It is further contemplated that esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, and combinations thereof, may be used. Esters of 13-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, and combinations thereof, may also be used. Moreover, esters of 3,5-di-tert-butyl-4-hydroxyphenyl acetic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, and combinations thereof, may be utilized.

Additional non-limiting examples of suitable additional antioxidants include those that include nitrogen, such as amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid e.g. N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine, N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine, N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyphydrazine. Other suitable non-limiting examples of additional antioxidants include aminic antioxidants such as N,N′-diisopropyl-p-phenylenediamine, N,N′-di-sec-butyl-p-phenylenediamine, N,N′-bis (1,4-dimethylpentyl)-p-phenylenediamine, N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, N,N′-bis(1-methylheptyl)-p-phenylenediamine, N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine, N,N′-bis(2-naphthyl)-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, N-(1,3-dimethyl-butyl)-N′-phenyl-p-phenylenediamine, N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine, N-cyclohexyl-N′-phenyl-p-phenylenediamine, 4-(p-toluenesulfamoyl)diphenylamine, N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxydiphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, octylated diphenylamine, for example p,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol, 4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol, 4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine, 2,6-di-tert-butyl-4-dimethylamino methylphenol, 2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, N,N,N′,N′-tetramethyl-4,4′-diaminodiphenylmethane, 1,2-bis[(2-methyl-phenyl)amino]ethane, 1,2-bis(phenylamino)propane, (o-tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine, tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- and dialkylated tert-butyl/tert-octyldiphenylamines, a mixture of mono- and dialkylated isopropyl/isohexyldiphenylamines, mixtures of mono- and dialkylated tert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine, phenothiazine, N-allylphenothiazine, N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene, N,N-bis(2,2,6,6-tetramethylpiperid-4-yl-hexamethylenediamine, bis(2,2,6,6-tetramethylpiperid-4-yl)sebacate, 2,2,6,6-tetramethylpiperidin-4-one and 2,2,6,6-tetramethyl piperidin-4-ol, and combinations thereof.

Even further non-limiting examples of suitable additional antioxidants includes aliphatic or aromatic phosphites, esters of thiodipropionic acid or of thiodiacetic acid, or salts of dithiocarbamic or dithiophosphoric acid, 2,2,12,12-tetramethyl-5,9-dihydroxy-3,7,1trithiatridecane and 2,2,15,15-tetramethyl-5,12-dihydroxy-3,7,10,14-tetrathiahexadecane, and combinations thereof. Furthermore, sulfurized fatty esters, sulfurized fats and sulfurized olefins, and combinations thereof, may be used. Some of the aforementioned antioxidants may represent, in chemical description, one or more of the first, second, and third antioxidants. These may be utilized. In addition, any one or more of the other antioxidants described above may also be used to supplement one or more of the first, second, and third antioxidants.

The one or more additional antioxidants are not particularly limited in amount in the composition but may be present in an amount of from 0.1 to 2, 0.5 to 2, 1 to 2, or 1.5 to 2, parts by weight per 100 parts by weight of the composition. Alternatively, the one or more additional antioxidants may be present in amounts of less than 2, less than 1.5, less than 1, or less than 0.5, parts by weight per 100 parts by weight of the composition. Of course, the weight percent of the one or more antioxidants may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may be present in amounts that vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Metal Deactivators:

In various embodiments, one or more metal deactivators can be included in the composition. Suitable, non-limiting examples of the one or more metal deactivators include benzotriazoles and derivatives thereof, for example 4- or 5-alkylbenzotriazoles (e.g. triazole) and derivatives thereof, 4,5, 6,7-tetrahydrobenzotriazole and 5,5′-methylenebisbenzotriazole; Mannich bases of benzotriazole or triazole, e.g. 1-[bis(2-ethylhexyl)aminomethyl)triazole and 1-[bis(2-ethylhexyl)aminomethyl)benzotriazole; and alkoxyalkylbenzotriazoles such as 1-(nonyloxymethyl)benzotriazole, 1-(1-butoxyethyl)benzotriazole and 1-(1-cyclohexyloxybutyl) triazole, and combinations thereof.

Additional non-limiting examples of the one or more metal deactivators include 1,2,4-triazoles and derivatives thereof, for example 3-alkyl(or aryl)-1,2,4-triazoles, and Mannich bases of 1,2,4-triazoles, such as 1-[bis(2-ethylhexyl)aminomethyl-1,2,4-triazole; alkoxyalkyl-1,2,4-triazoles such as 1-(1-butoxyethyl)-1,2,4-triazole; and acylated 3-amino-1,2,4-triazoles, imidazole derivatives, for example 4,4′-methylenebis(2-undecyl-5-methylimidazole) and bis[(N-methyl)imidazol-2-yl]carbinol octyl ether, and combinations thereof.

Further non-limiting examples of the one or more metal deactivators include sulfur-containing heterocyclic compounds, for example 2-mercaptobenzothiazole, 2,5-dimercapto-1,3,4-thiadiazole and derivatives thereof; and 3,5-bis[di(2-ethylhexyl)aminomethyl]-1,3,4-thiadiazolin-2-one, and combinations thereof. Even further non-limiting examples of the one or more metal deactivators include amino compounds, for example salicylidenepropylenediamine, salicylaminoguanidine and salts thereof, and combinations thereof.

The one or more metal deactivators are not particularly limited in amount in the composition but are typically present in an amount of from 0.01 to 0.1, from 0.05 to 0.01, or from 0.07 to 0.1, parts by weight per 100 parts by weight of the composition. Alternatively, the one or more metal deactivators may be present in amounts of less than 0.1, of less than 0.7, or less than 0.5, parts by weight per 100 parts by weight of the composition. The weight percent of the one or more metal deactivators may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may be present in amounts that vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Rust Inhibitors and Friction Modifiers:

In various embodiments, one or more additional rust inhibitors and/or one or more friction modifiers can be included in the composition. Suitable, non-limiting examples of the one or more additional rust inhibitors and/or one or more friction modifiers include organic acids, their esters, metal salts, amine salts and anhydrides, for example alkyl- and alkenylsuccinic acids and their partial esters with alcohols, diols or hydroxycarboxylic acids, partial amides of alkyl- and alkenylsuccinic acids, 4-nonylphenoxyacetic acid, alkoxy- and alkoxyethoxycarboxylic acids such as dodecyloxyacetic acid, dodecyloxy(ethoxy)acetic acid and the amine salts thereof, and also N-oleoylsarcosine, sorbitan monooleate, lead naphthenate, alkenylsuccinic anhydrides, for example dodecenylsuccinic anhydride, 2-carboxymethyl-1-dodecyl-3-methylglycerol and the amine salts thereof, and combinations thereof. Additional suitable, non-limiting examples of the one or more rust inhibitors and/or friction modifiers include nitrogen-containing compounds, for example, primary, secondary or tertiary aliphatic or cycloaliphatic amines and amine salts of organic and inorganic acids, for example oil-soluble alkylammonium carboxylates, and also 1-[N,N-bis(2-hydroxyethyl)amino]-3-(4-nonylphenoxy)propan-2-ol, and combinations thereof. Further suitable, non-limiting examples include heterocyclic compounds, for example: substituted imidazolines and oxazolines, and 2-heptadecenyl-1-(2-hydroxyethyl)imidazoline, phosphorus-containing compounds, for example: Amine salts of phosphoric acid partial esters or phosphonic acid partial esters, and zinc dialkyldithiophosphates, molybdenum-containing compounds, such as molydbenum dithiocarbamate and other sulfur and phosphorus containing derivatives, sulfur-containing compounds, for example: barium dinonylnaphthalenesulfonates, calcium petroleum sulfonates, alkylthio-substituted aliphatic carboxylic acids, esters of aliphatic 2-sulfocarboxylic acids and salts thereof, glycerol derivatives, for example: glycerol monooleate, 1-(alkylphenoxy)-3-(2-hydroxyethyl)glycerols, 1-(alkylphenoxy)-3-(2,3-dihydroxypropyl) glycerols and 2-carboxyalkyl-1,3-dialkylglycerols, and combinations thereof.

The one or more additional rust inhibitors and/or one or more friction modifiers are not particularly limited in amount in the composition but may be present in an amount of from 0.05 to 0.5, 0.01 to 0.2, from 0.05 to 0.2, 0.1 to 0.2, 0.15 to 0.2, or 0.02 to 0.2, parts by weight per 100 parts by weight of the composition. Alternatively, the one or more additional rust inhibitors and/or one or more friction modifiers may be present in amounts of less than 0.5, less than 0.4, less than 0.3, less than 0.2, less than 0.1, less than 0.5, or less than 0.1, parts by weight per 100 parts by weight of the composition. The weight percent of the one or more rust inhibitors and friction modifiers may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may be present in amounts that vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Viscosity Index Improvers:

In various embodiments, one or more viscosity index improvers can be included in the composition. Suitable, non-limiting examples of the one or more viscosity index improvers include polyacrylates, polymethacrylates, vinylpyrrolidone/methacrylate copolymers, polyvinylpyrrolidones, polybutenes, olefin copolymers, styrene/acrylate copolymers and polyethers, and combinations thereof. The one or more viscosity index improvers are not particularly limited in amount in the composition but are typically present in an amount of from 1 to 1, from 2 to 8, from 3 to 7, from 4 to 6, or from 4 to 5, parts by weight per 100 parts by weight of the composition. Alternatively, the one or more viscosity index improvers may be present in an amount of less than 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1, part by weight per 100 parts b eight of the composition. The weight percent of the one or more viscosity index improvers may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may be present in amounts that vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Pour Point Depressants:

In various embodiments, one or more pour point depressants can be included in the composition. Suitable, non-limiting examples of the pour point depressants include polymethacrylate and alkylated naphthalene derivatives, and combinations thereof. The one or more pour point depressants are not particularly limited in amount in the composition but are typically present in an amount of from 0.1 to 1, from 0.5 to 1, or from 0.7 to 1, part by weight per 100 parts by weight of the composition. Alternatively, the one or more pour point depressants may be present in amounts of less than 1, less than 0.7, or less than 0.5, parts by weight per 100 parts by weight of the composition. The weight percent of the one or more pour point depressants may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may be present in amounts that vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Dispersants:

In various embodiments, one or more dispersants can be included in the composition. Suitable, non-limiting examples of the one or more dispersants include polybutenylsuccinic amides or -imides, polybutenylphosphonic acid derivatives and basic magnesium, calcium and barium sulfonates and phenolates, succinate esters and alkylphenol amines (Mannich bases), and combinations thereof.

The one or more dispersants are not particularly limited in amount in the composition but are typically present in an amount of from 0.1 to 5, from 0.5 to 4.5, from 1 to 4, from 1.5 to 3.5, from 2 to 3, or from 2.5 to 3, parts by weight per 100 parts by weight of the composition. Alternatively, the one or more dispersants may be present in an amount of less than 5, 4.5, 3.5, 3, 2.5, 2, 1.5, or 1, part by weight per 100 parts by weight of the composition. The weight percent of the one or more dispersants may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may be present in amounts that vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Detergents:

In various embodiments, one or more detergents can be included in the composition. Suitable, non-limiting examples of the one or more detergents include overbased or neutral metal sulphonates, phenates and salicylates, and combinations thereof.

The one or more detergents are not particularly limited in amount in the composition but are typically present in an amount of from 0.1 to 5, from 0.5 to 4.5, from 1 to 4, from 1.5 to 3.5, from 2 to 3, or from 2.5 to 3, parts by weight per 100 parts by weight of the composition. Alternatively, the one or more detergents may be present in an amount of less than 5, 4.5, 3.5, 3, 2.5, 2, 1.5, or 1, part by weight per 100 parts by weight of the composition. The weight percent of the one or more detergents may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may be present in amounts that vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

In various embodiments, the composition is substantially free of water, e.g. includes less than 5, 4, 3, 2, or 1, weight percent of water. Alternatively, the composition may include less than 0.5 or 0.1 weight percent of water or may be free of water. Of course, the weight percent of the water may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may be present in amounts that vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Additive Concentrate Package:

The instant disclosure also provides an additive concentrate package which includes one or more metal deactivators, one or more anti-wear additives, and the antioxidant component. In various embodiments, the additive concentrate package may include one or more additional additives as described above. The additive package may be included in the composition in amounts of from 0.1 to 1, from 0.2 to 0.9, from 0.3 to 0.8, from 0.4 to 0.7, or from 0.5 to 0.6, parts by weight per 100 parts by weight of the composition. The weight percent of the additive concentrate package may be any value or range of values, both whole and fractional, within those ranges and values described above and/or may be present in amounts that vary from the values and/or range of values above by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Some of the compounds described above may interact in the lubricant composition, so the components of the lubricant composition in final form may be different from those components that are initially added or combined together. Some products formed thereby, including products formed upon employing the composition of this disclosure in its intended use, are not easily described or describable. Nevertheless, all such modifications, reaction products, and products formed upon employing the composition of this disclosure in its intended use, are expressly contemplated and hereby included herein. Various embodiments of this disclosure include one or more of the modification, reaction products, and products formed from employing the composition, as described above.

Oxidation Induction Time:

As is known in the art, oxidation induction time, as determined using ASTM D6186, may be used as an indication of oxidation stability of the lubricant composition. This test method tends to be faster than other oil oxidation tests and requires a very small amount of sample. This test method may be used for research and development, quality control, and specification purposes. This test method covers the determination of oxidation induction time of lubricating oils subjected to oxygen at 3.5 MPa (500 psig) and temperatures between 130 and 210° C.

Typically, a small quantity of the composition is weighed into a sample pan and placed in a test cell. The cell is heated to a specified temperature and then pressurized with oxygen. The cell is held at a regulated temperature and pressure until an exothermic reaction occurs. The extrapolated onset time is measured and reported as the oxidation induction time for the composition at the specified test temperature. The oxidation induction time of various embodiments of this disclosure is increased as compared to the oxidation induction time of comparative examples that include the same base oil and just one or two of the first, second, and third antioxidants. In other words, the specific combination of the first, second, and third antioxidants provides an unexpected synergistic increase in oxidation induction times that is not predicted by those of skill in the art. In various embodiments, the oxidation induction time of the composition is greater than 10, 10.5, 11, 11.5, 12, 12.5, or even greater, minutes, as determined using ASTM D6186. In various embodiments, the maximum oxidation induction time is 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, or 20, minutes. In various non-limiting embodiments, all values and range of values, both whole and fractional, within those ranges and values described above, including the endpoints, are hereby expressly contemplated. Moreover, any of the aforementioned values may vary by ±5%, ±10%, ±15%, ±20%, ±25%, ±30%, etc.

Without intending to be bound by any particular theory, it is believed that the second antioxidant has an NH bond that is readily cleaved allowing nitrogen to pick up a free radical from the base oil and stop a catalytic cycle. Moreover, it is believed that the third antioxidant functions due to steric hindrance of the —OH group thereby preventing or minimizing a nucleophilic reaction. As a type of hindered phenol, the hydrogen atom of the third antioxidant may be abstracted and generate its own radical which allows the third antioxidant to pick up a radical from the base oil.

Method of Forming the Composition:

This disclosure also provides a method of forming the composition. The method includes the steps of providing the base oil, providing the antioxidant component and combining the base oil and the antioxidant component to form the composition. The method may also include the step of combining any or more of the aforementioned additives with the base oil and/or the antioxidant component. The base oil, the antioxidant component, and any one or more optional additives may be combined in any order and each individually in one or more separate parts.

Method for Reducing Corrosion of a Steel Article:

This disclosure also provides a method for reducing corrosion of a steel article using the composition. The method includes the steps of providing the base oil and providing the antioxidant component. The method also includes the steps of combining the base oil and the antioxidant component to form the composition and applying the composition to the steel article to reduce corrosion.

Method for Reducing Wear of a Metal:

This disclosure also provides a method for reducing wear of a metal, e.g. a metal article. The method may include any one or more of the aforementioned method steps. The method of reducing wear of the metal includes the step of providing the metal and the step of applying the lubricant composition to the metal.

The step of providing the metal can occur before, after, or simultaneously with, the optional steps of providing the base oil, providing the antioxidant component, and/or combining the base oil and the antioxidant component and any one or more optional additives to form a lubricant composition.

EXAMPLE S

An inventive composition is formed in addition to various comparative compositions. The comparative compositions differ from the inventive composition in that none of the comparative compositions include all three of the first, second, and third antioxidants. After formation, each of the inventive composition and the comparative compositions is evaluated to determine oxidation induction time according to ASTM D6186. The compositions and the results of the oxidation induction time testing are set forth below.

Invent. 1 Comp. 1 Comp. 2 Comp. 3 Comp. 4 Comp. 5 Comp. 6 Base Oil 98.14%  99.5% 99.14% 99.5% 99.0% 98.64% 98.64% Antioxidant 1 0.86%  — 0.86% — —  0.86%  0.86% Antioxidant 2 0.5% 0.5% — — 0.5%  0.5% — Antioxidant 3 0.5% — — 0.5 0.5% —  0.5% Oxidation 12.3 4.6 1.5 3.3 8.3 5.8 8.8 Induction Time (min)

Base Oil is a Group II base oil.

Antioxidant 2 is an aminic antioxidant that has the structure:

wherein R² is a octyl group and R³ is a butyl group.

Antioxidant 1 is a hindered amine antioxidant that has the structure:

wherein R is a straight alkyl group having 11 carbon atoms.

Antioxidant 3 is a phenolic antioxidant that has the structure:

wherein m is 1 and R⁴ is C₈H₁₇.

The data clearly indicates a special, superior, and unexpected synergistic effect when all three of the aforementioned antioxidants are combined. For example:

When Antioxidant 1 is used by itself, the oxidation induction time is 1.5 minutes;

When Antioxidant 2 is used by itself, the oxidation induction time 4.6 minutes;

When Antioxidant 3 is used by itself, the oxidation induction time is 3.3 minutes;

Therefore, if Antioxidants 1, 2, and 3 were used together, the expected outcome would be additive and would be approximately 9.4 minutes. However, the actual result is 12.3 minutes which is an unexpected 31% higher. Clearly, this is both superior and unexpected.

All combinations of the aforementioned embodiments throughout the entire disclosure are hereby expressly contemplated in one or more non-limiting embodiments even if such a disclosure is not described verbatim in a single paragraph or section above. In other words, an expressly contemplated embodiment may include any one or more elements described above selected and combined from any portion of the disclosure.

One or more of the values described above may vary by ±5%, ±10%, ±15%, ±20%, ±25%, etc. so long as the variance remains within the scope of the disclosure. Unexpected results may be obtained from each member of a Markush group independent from all other members. Each member may be relied upon individually and or in combination and provides adequate support for specific embodiments within the scope of the appended claims. The subject matter of all combinations of independent and dependent claims, both singly and multiply dependent, is herein expressly contemplated. The disclosure is illustrative including words of description rather than of limitation. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described herein.

It is also to be understood that any ranges and subranges relied upon in describing various embodiments of the present disclosure independently and collectively fall within the scope of the appended claims, and are understood to describe and contemplate all ranges including whole and/or fractional values therein, even if such values are not expressly written herein. One of skill in the art readily recognizes that the enumerated ranges and subranges sufficiently describe and enable various embodiments of the present disclosure, and such ranges and subranges may be further delineated into relevant halves, thirds, quarters, fifths, and so on. As just one example, a range “of from 0.1 to 0.9” may be further delineated into a lower third, i.e. from 0.1 to 0.3, a middle third, i.e. from 0.4 to 0.6, and an upper third, i.e. from 0.7 to 0.9, which individually and collectively are within the scope of the appended claims, and may be relied upon individually and/or collectively and provide adequate support for specific embodiments within the scope of the appended claims. In addition, with respect to the language which defines or modifies a range, such as “at least,” “greater than,” “less than,” “no more than,” and the like, it is to be understood that such language includes subranges and/or an upper or lower limit. As another example, a range of “at least 10” inherently includes a subrange of from at least 10 to 35, a subrange of from at least 10 to 25, a subrange of from 25 to 35, and so on, and each subrange may be relied upon individually and/or collectively and provides adequate support for specific embodiments within the scope of the appended claims. Finally, an individual number within a disclosed range may be relied upon and provides adequate support for specific embodiments within the scope of the appended claims. For example, a range “of from 1 to 9” includes various individual integers, such as 3, as well as individual numbers including a decimal point (or fraction), such as 4.1, which may be relied upon and provide adequate support for specific embodiments within the scope of the appended claims. 

What is claimed is:
 1. A lubricant composition having an increased oxidation induction time determined according to ASTM D6186 and comprising: a base oil present in an amount of greater than 85 parts by weight per 100 parts by weight of said lubricant composition; and an antioxidant component comprising; a first antioxidant having the structure,

wherein R is a straight or branched alkyl group having 7 to 17 carbon atoms, and wherein n is from 6 to 18, a second antioxidant having the structure:

wherein each of A, D, E and G is carbon or nitrogen and wherein R² and R³ are each independently chosen from hydrogen, alkyl, N-(alkyl)₂, styryl, and α-alkyl styryl groups, provided that at least one of R² and R³ is not hydrogen, and a third antioxidant having the structure:

wherein m is a number from 1 to 10 and R⁴ is hydrogen or an alkyl group having 1 to 12 carbon atoms, and wherein R⁵ is an alkyl group having 1 to 20 carbon atoms and each of R⁶ and R⁷ is independently —CH₂—S-alkyl, wherein the alkyl group bonded to the sulfur atom has 1 to 20 carbon atoms.
 2. The lubricant composition of claim 1 wherein said first, second, and third antioxidants are present in a ratio of from 0.1:0.1:0.1 to 3:5:5.
 3. The lubricant composition of claim 1 wherein R is a straight or branched alkyl group of 11 or 17 carbon atoms.
 4. The lubricant composition of claim 1 wherein R is a straight or branched alkyl group of 8 to 14 carbon atoms.
 5. The lubricant composition of claim 1 wherein R is a straight or branched alkyl group of 10 to 14 carbon atoms.
 6. The lubricant composition of claim 1 wherein R is a straight or branched alkyl group of 10 to 12 carbon atoms.
 7. The lubricant composition of claim 1 wherein R is a straight or branched alkyl group of 11 atoms.
 8. The lubricant composition of claim 1 wherein said second antioxidant has the structure:

wherein each of A, D, E, and G is a carbon atom, R² is an octyl group, and R³ is a butyl group.
 9. The lubricant composition of claim 1 wherein said second antioxidant has the structure:

wherein at least two of A, D, E and G are nitrogen atoms and wherein R² and R³ are each independently hydrogen or N-(alkyl)₂ wherein the alkyl group has 1 to 20 carbon atoms.
 10. The lubricant composition of claim 1 wherein said second antioxidant has the structure:

wherein at least one of A, D, E and G is a nitrogen atom and wherein R² and R³ are each independently hydrogen or N-(alkyl)₂ wherein the alkyl group has 1 to 20 carbon atoms.
 11. The lubricant composition of claim 1 wherein said third antioxidant has the structure:

wherein m is 1 and R⁴ is:


12. The lubricant composition of claim 1 wherein said third antioxidant has the structure:

m is 1 and R⁴ is C₈H₁₇.
 13. The lubricant composition of claim 1 wherein said third antioxidant has the structure:

wherein R⁵ is a methyl group and each of R⁶ and R⁷ is independently —CH₂—S—C₈H₁₇.
 14. The lubricant composition of claim 1 wherein said base oil is further defined as an API Group II, Group III or Group IV oil.
 15. The lubricant composition of claim 1 having an oxidation induction time of greater than 10 minutes determined according to ASTM D6186.
 16. The lubricant composition of claim 1 having an oxidation induction time of greater than 12 minutes determined according to ASTM D6186.
 17. The lubricant composition of claim 1 having an oxidation induction time of greater than 12 minutes determined according to ASTM D6186, wherein said base oil is further defined as an API Group II oil, wherein said first antioxidant has the structure:

wherein R is a straight alkyl group having 11 carbon atoms, wherein said second antioxidant having the structure:

wherein each of A, D, E, and G is a carbon atom, R² is an octyl group, and R³ is a butyl group, and wherein said third antioxidant having the structure:

wherein m is 1 and R⁴ is:

and wherein said first, second, and third antioxidants are present in a ratio of from 0.1:0.1:0.1 to 3:5:5.
 18. A method of forming the lubricant composition of claim 1 wherein the method comprises the step of combining the base oil and the antioxidant component to form the lubricant composition.
 19. A method of reducing corrosion of a steel article, said method comprising the steps of: A. providing a base oil; B. providing an antioxidant component comprising; a first antioxidant having the structure,

wherein R is a straight or branched alkyl group having 7 to 17 carbon atoms, and wherein n is from 6 to 18, a second antioxidant having the structure:

wherein each of A, D, E and G is carbon or nitrogen and wherein R² and R³ are each independently chosen from hydrogen, alkyl, N-(alkyl)₂, styryl, and α-alkyl styryl groups, provided that at least one of R² and R³ is not hydrogen, and a third antioxidant having the structure:

wherein m is a number from 1 to 10 and R⁴ is hydrogen or an alkyl group having 1 to 12 carbon atoms, and wherein R⁵ is an alkyl group having 1 to 20 carbon atoms and each of R⁶ and R⁷ is independently —CH₂—S-alkyl, wherein the alkyl group bonded to the sulfur atom has 1 to 20 carbon atoms, C. combining the base oil and the antioxidant component to form the lubricant composition wherein the base oil is present in an amount of greater than 85 parts by weight per 100 parts by weight of the lubricant composition; and D. applying the lubricant composition to the steel article; wherein the composition has an oxidation induction time of greater than 10 minutes determined according to ASTM D6186.
 20. The method of claim 19 wherein the composition has an oxidation induction time of greater than 12 minutes determined according to ASTM D6186, wherein the base oil is further defined as an API Group II oil, wherein the first antioxidant has the structure:

wherein R is a straight alkyl group having 11 carbon atoms, wherein the second antioxidant having the structure:

wherein each of A, D, E, and G is a carbon atom, R² is an octyl group, and R³ is a butyl group, and wherein the third antioxidant having the structure:

wherein m is 1 and R⁴ is:

and wherein the first, second, and third antioxidants are present in a ratio of from 0.1:0.1:0.1 to 3:5:5 